Background/Purpose: In the presence of limited available data, our objective was to assess the association of gout with the risk of incident Parkinson’s disease (PD) in older adults ³65 years.

Methods: We used the 5% Medicare claims data from 2006-2012 for this cohort study. Gout was identified by the presence of two claims for gout at least 4 weeks apart, with International Classification of Diseases, ninth revision, common modification (ICD-9-CM) code of 274.xx. Study outcome was incident GCA, identified by two claims for PD with an ICD-9-CM code of 446.5, at least 4 weeks apart and an absence of PD claims in the baseline 365-day period, a valid approach. We used multivariable-adjusted Cox proportional hazard models to assess the association of gout with incident GCA, adjusting for potential confounders/covariates including demographics (age, race, gender), comorbidities (Charlson-Romano comorbidity index), and medications commonly used for cardiac diseases (statins, beta-blockers, diuretics, and angiotensin converting enzyme (ACE)-inhibitors) and gout (allopurinol and febuxostat; Model 1).  

Results: In a cohort of 1.72 million people, the mean age was 75 years (standard deviation [SD], 7.6), mean Charlson-Romano comorbidity index score was 1.60 (SD, 2.39), 58% were female, 86% were White and 37% had Charlson-Romano comorbidity index score of ≥2. Of these, 22,636 people developed incident PD during the study follow-up, 1,129 with gout and 21,507 without gout, with respective crude incidence rates of incident PD of 3.7 vs. 2.2 per 1,000 person-years, respectively. Gout was associated with a higher risk of PD in the main analysis, 1.14 (95% CI, 1.07, 1.21). Sensitivity analyses confirmed main findings. No gender or race differences were noted, but the risk differed slightly by age; ages 65-75, 75-85 and >85 had hazard ratios of incident PD with gout of 1.27 (95% CI, 1.16, 1.39), 1.07 (95% CI, 0.97, 1.16) and 0.97 (95% CI, 0.79, 1.20), respectively (Table 1). 

Conclusion: Gout was associated with a higher risk of incident PD in older adults. The risk of PD with gout was highest in the age group 65-75 years. Mechanisms of this increased risk need to be evaluated in future studies.